<template>
  <div class="camera_outer" @click="setImage">
    <video id="videoCamera" :width="videoWidth" :height="videoHeight" autoplay></video>
    <canvas style="display:none;" id="canvasCamera" :width="videoWidth" :height="videoHeight"></canvas>
    <!-- <img :src="src" class="bg_r_img" /> -->
    <div v-if="imgSrc" class="img_bg_camera">
      <img :src="imgSrc" alt class="tx_img" />
      <div class="img_btn_camera" @click.stop="back">
        {{validTip}}
        <!-- <img v-if="validTip === '验证中'" src="alt" class="loding_img" /> -->
      </div>
    </div>
    <div v-else class="btn_camera">把您的脸至于圆圈中央</div>
  </div>
</template>
<script>
export default {
  data() {
    return {
      videoWidth: 540,
      videoHeight: 410,
      imgSrc: "",
      thisCancas: null,
      thisContext: null,
      thisVideo: null,
      validTip: "验证中"
    };
  },
  computed: {},
  methods: {
    /*
     *@author wf_Huang
     *@Time 2019/6/5 0005 17:35
     *@function  调用权限
     *****************************************/
    getCompetence() {
      var _this = this;
      this.thisCancas = document.getElementById("canvasCamera");
      this.thisContext = this.thisCancas.getContext("2d");
      this.thisVideo = document.getElementById("videoCamera");
      // 旧版本浏览器可能根本不支持mediaDevices，我们首先设置一个空对象
      if (navigator.mediaDevices === undefined) {
        navigator.mediaDevices = {};
      }
      // 一些浏览器实现了部分mediaDevices，我们不能只分配一个对象
      // 使用getUserMedia，因为它会覆盖现有的属性。
      // 这里，如果缺少getUserMedia属性，就添加它。
      if (navigator.mediaDevices.getUserMedia === undefined) {
        navigator.mediaDevices.getUserMedia = function(constraints) {
          // 首先获取现存的getUserMedia(如果存在)
          var getUserMedia =
            navigator.webkitGetUserMedia ||
            navigator.mozGetUserMedia ||
            navigator.getUserMedia;
          // 有些浏览器不支持，会返回错误信息
          // 保持接口一致
          if (!getUserMedia) {
            return Promise.reject(
              new Error("getUserMedia is not implemented in this browser")
            );
          }
          // 否则，使用Promise将调用包装到旧的navigator.getUserMedia
          return new Promise(function(resolve, reject) {
            getUserMedia.call(navigator, constraints, resolve, reject);
          });
        };
      }
      var constraints = {
        audio: false,
        video: {
          width: this.videoWidth,
          height: this.videoHeight,
          transform: "scaleX(-1)"
        }
      };
      navigator.mediaDevices
        .getUserMedia(constraints)
        .then(function(stream) {
          // 旧的浏览器可能没有srcObject
          if ("srcObject" in _this.thisVideo) {
            _this.thisVideo.srcObject = stream;
          } else {
            // 避免在新的浏览器中使用它，因为它正在被弃用。
            _this.thisVideo.src = window.URL.createObjectURL(stream);
          }
          _this.thisVideo.onloadedmetadata = function() {
            _this.thisVideo.play();
          };
        })
        .catch(err => {
          console.log(err);
        });
    },
    /*
     *@author wf_Huang
     *@Time 2019/6/5 0005 17:32
     *@function  绘制图片
     *****************************************/
    setImage() {
      var _this = this;
      // 点击，canvas画图
      _this.thisContext.drawImage(
        _this.thisVideo,
        0,
        0,
        _this.videoWidth,
        _this.videoHeight
      );
      // 获取图片base64链接
      var image = this.thisCancas.toDataURL("image/png");
      _this.imgSrc = image;
      this.$emit("refreshDataList", this.imgSrc);
      console.log(image);
      //关闭摄像头
      this.stopNavigator();
    },
    /*
     *@author wf_Huang
     *@Time 2019/6/5 0005 17:44
     *@function  base64转文件
     *****************************************/
    dataURLtoFile(dataurl, filename) {
      var arr = dataurl.split(",");
      var mime = arr[0].match(/:(.*?);/)[1];
      var bstr = atob(arr[1]);
      var n = bstr.length;
      var u8arr = new Uint8Array(n);
      while (n--) {
        u8arr[n] = bstr.charCodeAt(n);
      }
      return new File([u8arr], filename, { type: mime });
    },
    /*
     *@author wf_Huang
     *@Time 2019/6/10 0010 3:41
     *@function  关闭摄像头
     *****************************************/
    stopNavigator() {
      this.thisVideo.srcObject.getTracks()[0].stop();
    },

    back() {
      console.log("表示已经退出拍照路由！");
      this.$router.back();
    }
  },
  mounted() {
    this.getCompetence();
  },
  beforeDestroy() {
    this.stopNavigator();
  },
  beforeRouteLeave(to, form, next) {
    this.stopNavigator();
    next();
  }
};
</script>
<style lang="scss" scoped>
.camera_outer {
  width: 100vw;
  height: 100vh;
  position: fixed;
  top: 0;
  left: 0;
  z-index: 100;
  background-color: #fff;
  position: relative;
  overflow: hidden;
  //   background: url("../../assets/img/user_0608_04.png") no-repeat center;
  background-size: 100%;
  video,
  canvas,
  .tx_img {
    -moz-transform: scaleX(-1);
    -webkit-transform: scaleX(-1);
    -o-transform: scaleX(-1);
    transform: scaleX(-1);
  }
  .btn_camera {
    position: absolute;
    bottom: 110px;
    left: 0;
    right: 0;
    height: 50px;
    background-color: rgba(0, 0, 0, 0.3);
    line-height: 50px;
    text-align: center;
    color: #ffffff;
  }
  .bg_r_img {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    top: 0;
  }
  .img_bg_camera {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    top: 0;
    z-index: 99;
    img {
      width: 540px;
      height: 410px;
    }
    .img_btn_camera {
      position: absolute;
      bottom: 110px;
      left: 0;
      right: 0;
      height: 50px;
      line-height: 50px;
      z-index: 999;
      text-align: center;
      background-color: rgba(0, 0, 0, 0.3);
      color: #ffffff;
      .loding_img {
        width: 50px;
        height: 50px;
      }
    }
  }
}
</style>